1. 13.3 Images in Lenses

2. Sideways Displacement in a rectangular prism
The emergent ray will always be parallel to the incident ray, but displaced sideways.
The amount of displacement depends on the thickness of the prism.
See Fig. 1 p. 557

3. Relevance?
This is the same with lenses. The greater the thickness, or curvature, the greater the refraction.

4. Rules for Locating the Image in a Converging Lens
A ray parallel to the principal axis is refracted through the principal focus.
A ray through the secondary principal focus (F’) is refracted parallel to the principal axis.
A ray through the optical centre continues straight through.

6. Images in a Converging Lens
Case 1: Beyond 2F’
Case 2: At 2F’
Case 3: Between 2F’ and F’
Case 4: At F’
Case 5: Inside F’

7. Case 1: Beyond 2F’

8. Case 2: At 2F’

9. Case 3: Between 2F’ and F’

10. Case 4: At F’

11. Case 5: Inside F’

12. Summary

13. Imaging Properties of a Converging Lens (Table 1, pg 559)
Object
Image
Location
Size
Attitude
Type
Beyond 2F’
At 2F’
Between 2F’ and F’
At F’
Inside F’
Between 2F and F
Smaller
Inverted
Real
Same
Inverted
At 2F
Real
Larger
Inverted
Beyond 2F
Real
No Clear Image
Same Side as object
Larger
Upright
Virtual

14. Images in a Diverging Lens
A diverging lens always produces the same image characteristics no matter where the object is.
Always smaller, upright, on the same side of the lens as the object, and virtual.

15. Rules for Locating the Image in a Diverging Lens (pg 559)
A ray parallel to the principal axis is refracted as if it had come through the principal focus (F).
A ray that appears to pass through the secondary principal focus (F’) is refracted parallel to the principal axis.
A ray through the optical centre continues straight on its path.

16. Beyond 2F Between 2F&F At F

17. Image is always smaller, upright, same side as object, virtual
Summary
Image is always smaller, upright,
same side as object, virtual

18. Classwork
p. 561 # 1 – 5